Nowadays, mobile devices, such as mobile phones or tablets, do not comprise merely communication modules, such as 2G/3G or 4G mobile transceivers and/or Wi-Fi transceivers, but comprise also a set of sensors such as:                position sensors, including for example a Global Navigation Satellite System (GNSS) receiver, such as a Global Positioning System (GPS) receiver;        one or more accelerometers, such as tri-axial accelerometers and/or gyroscopes;        other environmental sensors, such as temperature, humidity, atmospheric pressure and/or magnetic sensors.        
These sensing and communication modules have usually low-power, low latency and high accuracy and permit the development and use of location and context-aware services. For example, currently more than 1 million of applications, so called Apps, are available through the main application stores for mobile devices and the applications having location and context enabled features are growing in number.
Generally, the ability to discriminate the user's activity and/or user's location depends on the type of primitive information/sensor data provided by the various sensors of the mobile device. For example, the application installed on the mobile device may be configured to process the sensor data in order to determine the activities the user of the mobile device is performing, for example in order to determine whether the user is stationary, walking, fast walking, running, using a bicycle or vehicle, shopping, watching TV, sleeping, waking-up, etc. Generally, the application may monitor, elaborate and/or store the sensor data and/or propose some tasks.
This has even lead to the development of wearable mobile devices, such as smart-watches or fitness bracelets, which represent a subgroup of mobile device possibly not even including a mobile communication module, and which often include sensors adapted to monitor physical parameters of the user, such as the heartbeat, blood pressure, etc.
Currently, most mobile devices do not include in-liquid sensors, i.e. sensors for determining whether the mobile device is immersed in a liquid, such as water.
Generally, a mobile device may comprise so called Liquid Contact Indicators (LCI). These LCIs are primarily one-time chemical indicators, for example based on sticker papers, that change color when in contact with a liquid, such as water. Typically, these indicators are built with a manufacturer signature for avoiding reproduction and are often arranged in the headphone connector, the dock connector, near the SIM-card slot or underneath the battery cover, for example near the battery contacts. These LCIs are commonly found in most types of mobile devices, such as mobile phones, portable music players, laptop computers, and other types of electronics and are basically used to indicate that the mobile device has been immersed in water and the warranty should not be valid anymore.
However, such chemical indicators may not be used as in-liquid sensors, because the indicators are unable to determine whether the mobile device has been removed from the liquid. For example, the indicators may not be used to provide additional environmental information and/or information concerning the user's activity, such as swimming. Possible other applications for in-liquid sensors may include the automatic adaption of the camera white-balance algorithm within the mobile device when diving.
Moreover, chemical indicators are often controversial, because some consumers claim they are unreliable and used to deny warranty coverage for devices that have not suffered water damage but have merely been exposed for longer periods to a high humidity level.
There is accordingly a need in the art to provide improved solutions for detecting the in liquid state of a mobile device.